A traction control system (TCS), also known as Anti-Slip Regulation (ASR), is typically, but not necessarily a secondary function of the anti lock braking system on production vehicles. It is designed to prevent loss of traction of the driven road wheels while maintaing the control of the vehicle when excessive throttle is applied by the driver and the condition of the road surface due to varying factors.

The intervention can consist of one or more of the following:

• Reduces or suppress the spark to one or more cylinders
• Reduce fuel supply to one or more cylinders
• Brake one or more wheels
• Close the throttle, if the vehicle is fitted with drive by wire throttle
• In turbo-charged vehicles, the boost control solenoid can be actuated to reduce boost and therefore engine power.

Typically, the traction control system shares the electro-hydraulic brake actuator, but does not use the conventional master cylinder and servo and the wheel speed sensors with the anti lock braking system